Method for placing discrete parts transversely onto a moving web

ABSTRACT

This invention pertains to processing continuous webs such as paper, film, composites, and the like, in dynamic continuous processing operations. More particularly, it relates to transferring discrete parts to a continuous web, whether paper, film, composite, or the like. Specifically, the invention relates to methods and apparatus for taking discrete parts from a source in a taking zone, optionally taking the discrete parts as components of a continuous web, onto a transport head on a transfer assembly, severing the discrete parts from the continuous web if received as part of a continuous web, rotating the transfer assembly about a first axis and correspondingly rotating the transport head about a second axis radial to the first axis, to thereby present the discrete parts to a receiver in a transfer zone, and transferring the discrete parts to the receiver in the transfer zone. The invention includes using a roughened taking section on the transport head, interacting with textured surface on the discrete parts, to hold the discrete parts to the transport head, with optional use of suction through the transport head to assist in holding the discrete parts to the transport head. Novel apparatus is included for delivering suction to and through rotating slip rings.

This application is a CIP of Ser. No. 08/186,352, filed Jan. 25, 1994,now U.S. Pat. No. 6,022,443, herein incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for receivingdiscrete parts travelling at a speed and applying the parts to a webtravelling at a different speed. The invention more particularlyconcerns a method and apparatus for receiving discrete parts of acontinuously moving web of material travelling at a certain speed andapplying the parts to a second continuously moving web travelling at adifferent speed.

BACKGROUND OF THE INVENTION

Articles, such as disposable diapers, generally have been manufacturedby a process where discrete parts or components of different materials,such as leg elastic, waist elastic, tapes and other fasteners such ashook and loop materials or snaps, have been applied to a continuouslymoving product web. Often, the speed at which the parts are fed into theprocess is not the same as the speed of the product web itself. Thus,the speed, and in some cases the orientation, of the parts must bechanged to match the speed and orientation of the product web toproperly apply the parts without adversely affecting the process or thefinished product.

Several different conventional methods for changing the speed of a partor component of material such that it can be applied to a continuouslymoving web have been known to those skilled in the art.

For example, one method has been known as the slip gap or slip cutmethod. A web of material, which is travelling at a slower speed thanthe moving web, is fed into a knife and anvil roll having a surfacespeed equal to the speed of the moving web. As the material is cut intodiscrete parts, vacuum in the anvil roll is activated to draw the partsof material to the surface of the anvil roll. The anvil roll thencarries the parts to the moving web where the vacuum is released and theparts are applied to the moving web while both the parts and the movingweb are travelling at the same speed.

Another method has utilized festoons to reduce the speed of the movingweb to match the speed of the discrete parts of material to be appliedto the web. The moving web is temporarily slowed down to the speed ofthe parts with the excess portion of the moving web gathering infestoons. The parts of material are then applied to the moving web whileboth the parts and the web are travelling at the same speed. Thefestoons are then released allowing the moving web to return to itsoriginal speed.

Another method has utilized a slider-crank mechanism to accomplish thespeed change. The slider-crank mechanism utilizes concentrically mountedarms or linkages to receive the discrete parts of material, increase thespeed of the parts to match the speed of the moving web and apply theparts to the moving web. The slider-crank mechanism is a special case ofa four bar linkage system.

Finally, another such method to change the speed of a discrete partbefore it is applied to a moving web has utilized a cam actuatedcrank-follower mechanism. The cam actuated crank-follower mechanismcomprises levers that are mounted on a rotatable driving plate. Eachlever has a pivot point and includes a cam follower on one end and adrag link on the other end. An applicator device is connected to theother end of the drag link. The cam follower remains in contact with afixed cam that is mounted concentric with the driving plate's center ofrotation. As the driving plate rotates, the levers pivot as their camfollowers follow the cam shape. As the levers pivot, the applicatordevices are caused to speed up or slow down. Thus, the mechanism can bedesigned to receive discrete parts of material, change the speed of theparts and apply the parts to a moving web. An example of this method isdescribed in U.S. Pat. No. 4,610,751 issued Sep. 9, 1986, to Eschler.

Conventional methods, such as those described above, have exhibitedseveral drawbacks. First, as the discrete parts of material aretransferred, they are often subjected to a tugging action because thesurface speed of the transfer means used to transfer the parts isgreater than the speed of the parts. The tugging action may result in anelongation or tear of the parts. Second, several of the conventionalmethods provide substantial speed variations but do not provide anyperiods where the speed remains constant for a fixed duration. Thus, thediscrete parts may be adversely affected because the surface speed ofthe transfer means used to transfer the parts is continuously changingduring the receiving and application process. Finally, several of theconventional methods can be very expensive and time consuming to changeas the size and speed of the discrete parts and the speed of the movingweb change to coincide with various finished product sizes.Consequently, an inexpensive and adaptable method for receiving discreteparts travelling at a first speed and applying the parts to a webtravelling at a different second speed is desirable.

Moreover, it is desirable that the receiving and applying of the partsoccurs while the respective surface speeds are maintained substantiallyconstant for a fixed duration. For example, it is desirable to apply theparts to the substrate web while the parts and substrate web aretravelling at substantially the same surface speed. A constant speeddwell allows precise control of the length and placement of the part onthe substrate web especially if the part is fragile and/or elastic.

Specifically, this invention relates to taking, transferring, andpresenting discrete parts including internally-contained elasticselements; and especially handling such discrete parts while theelongation in the elastics elements is maintained, with little or nosnap-back of the elongation.

It is an object of this invention to provide methods and apparatus fortaking the discrete parts at a first speed onto a transport head,rotating the transport head and the discrete parts about a first axis ata variable radial speed, and rotating the transport head about a secondaxis radial to the first axis.

It is another object to provide methods and apparatus for taking thediscrete parts onto the transport head while an arcuate top wall of thetransport head is disposed transverse to the direction of travel of thediscrete parts being received.

It is a further object to provide methods and apparatus for holding thediscrete parts on the transport head by providing a roughened surface onthe transport head, and a cooperating textured surface on the discreteparts.

It is yet another object to provide methods and apparatus for applyingsuction to the transport head through a central tubular conduit, a slipring about the conduit, and cooperating first and second arrays ofsuction ports in the slip ring and conduit to effect suction to thetransport head.

SUMMARY OF THE INVENTION

This invention describes apparatus and methods for receiving discreteparts, optionally as part of a continuous web, and transferring thediscrete parts, separated from the web, onto a receiver.

In a first family of embodiments, the invention contemplates a methodfor taking discrete parts travelling at a first speed in a firstdirection, and transferring the discrete parts to a receiver travellingat a second speed in a second direction, the method comprising the stepsof providing a rotatable transfer assembly, and at least one transporthead mounted on the transfer assembly, for taking the discrete partsonto the at least one transport head in a taking zone, and fortransferring the discrete parts to the receiver in a transfer zone;taking a discrete part onto the at least one transport head in thetaking zone wherein a leading edge of the discrete part is oriented at afirst angle “A” with respect to the first direction of travel; aftertaking the discrete part onto the at least one transport head, (i)rotating the rotatable transfer assembly about a first axis oriented ina third direction transverse to, and disposed in a plane parallel with,the first direction, at a variable angular velocity such that the atleast one transport head travels at a first surface speed whichsubstantially equals the first speed of the discrete part as thediscrete part is taken onto the at least one transport head in thetaking zone, and travels at a second surface speed which substantiallyequals the second speed of the receiver as the discrete part istransferred to the receiver in the transfer zone, the rotating of therotatable transfer assembly defining an orbital path, and (ii) rotatingthe transport head about a second radial axis intersecting the firstaxis and extending outwardly therefrom, to thereby orient the leadingedge of the discrete part at an angle “B” measured with respect to thesecond direction of travel of the receiver in the transfer zone,different from angle “A”; and transferring the so rotated discrete partto the receiver in the transfer zone.

The method preferably includes rotating the rotatable transfer assemblyabout the first axis while simultaneously rotating the transport headabout the second radial axis.

The method contemplates taking the discrete part onto the transport headas part of, and contained in, a continuous web, and cutting the web toseparate out the discrete part after taking the discrete part onto thetransport head and before rotating the transport head about the secondradial axis.

Preferably, the method also includes providing, on the transport head,an area having a roughened surface, and providing, on the discrete part,a textured surface, that interacts with the area of roughened surface onthe transport head to thereby secure the holding of the discrete part tothe transport head.

The method can include providing suction of about 1 to about 80 inchesof water, preferably at about 5 up to about 60 inches, more preferablyabout 45 inches of water, through the transport head to the discretepart, to enhance the holding of the discrete part to the transport headwhile rotating the rotatable transfer assembly from the taking zone tothe transfer zone.

In preferred members of this first family of embodiments, the transporthead has an arcuate top wall for receiving the discrete parts thereunto,the method including orienting the transport head such that thecurvature of the arcuate top wall is disposed transverse to the firstdirection of travel at the taking zone, and rotating the transport headabout the radial axis after taking the discrete part onto the transporthead, and thereby aligning the arcuate top wall with the receiver at thetransfer zone, whereby, after the rotation about the second radial axis,the arcuate top wall can, in the transfer zone, interact with asubstantially planar receiver disposed tangential to the orbital path,along a line transverse to the second direction in the transfer zone,and interacts with the discrete parts in the taking zone along a lineapproximating the first direction.

The method further comprises taking the discrete part while the discretepart is elongated and under tension exerted by elastics integral withthe discrete part, and including holding the discrete part to thetransport head with sufficient force that, when elastics integral withthe discrete part are elongated by e.g. 150%, in cooperation with afriction relationship between the transport head and the discrete part,the discrete part exhibits less than 50%, preferably less than 20%, morepreferably less than 10%, snap-back of the elongation while the discretepart is held on the transport head.

In a second family of embodiments, the invention contemplates a methodfor taking discrete parts travelling in a first direction and applyingthe discrete parts to a receiver travelling in a second direction, themethod comprising the steps of providing a rotatable transfer assembly,mounted for rotation in an orbital path about a first axis oriented in aplane parallel with the first direction, and at least one transport headmounted on the transfer assembly, for taking the discrete parts onto theat least one transport head in a taking zone, and for transferring thediscrete parts to the receiver in a transfer zone, the transport headhaving an arcuate top wall, including arcuate curvature thereon, fortaking the discrete parts, the transport head being mounted for rotationabout a second radial axis extending outwardly from the first axis;orienting the transport head such that the curvature of the arcuate topwall is disposed transverse to the first direction of travel; while thearcuate top wall is so disposed transverse to the first direction oftravel, taking a discrete part onto the at least one transport head inthe taking zone; after taking the discrete part onto the at least onetransport head, (i) rotating the rotatable transfer assembly about thefirst axis, and (ii) rotating the transport head, and the discrete partdisposed thereon, about the second radial axis, to thereby bring thecurvature of the arcuate top wall into alignment with the seconddirection of travel, and the transport head into proximity with thereceiver in the transfer zone; and transferring the so rotated discretepart to the receiver.

The method preferably includes rotating the rotatable transfer assemblyabout the first axis while simultaneously rotating the transport headabout the second radial axis, whereby, after the rotation about thesecond radial axis, the arcuate top wall can interact with asubstantially planar receiver disposed tangential to the orbital path,along a line transverse to the second direction in the transfer zone, aswell as interact with the discrete parts in the taking zone along a lineapproximating the first direction.

Preferably, the method of this second family of embodiments alsoincludes providing, on the transport head, an area having a roughenedsurface, and providing, on the discrete part, a textured surface, thetextured surface of the discrete part interacting with the area ofroughened surface on the transport head to thereby secure the holding ofthe discrete part to the transport head.

The method preferably includes holding the discrete part to thetransport head with suction while rotating the rotatable transferassembly from the taking zone to the transfer zone, to enhance theholding of the discrete part to the transport head.

In a third family of embodiments, the invention contemplates apparatusfor taking discrete parts travelling at a first speed in a firstdirection, and transferring the discrete parts to a receiver travellingat a second speed in a second direction, the apparatus comprising atransfer assembly mounted for rotation about a first axis oriented in athird direction transverse to, and disposed in a plane parallel with,the first direction; at least one transport head mounted on the transferassembly, for taking the discrete parts onto the at least one transporthead in a taking zone, wherein a leading edge of the discrete part isoriented at a first angle “A” with respect to the first direction oftravel, and for transferring the discrete parts to the receiver in atransfer zone; a first driver, for driving the transfer assembly aboutthe first axis, at a variable angular velocity such that the at leastone transport head travels at a first surface speed which substantiallyequals the first speed of the discrete part as the discrete part istaken onto the at least one transport head in the taking zone, andtravels at a second surface speed which substantially equals the secondspeed of the receiver as the discrete part is applied to the receiver inthe transfer zone, the rotating of the transfer assembly therebydefining an orbital path; and a second driver for rotating the transporthead about a second radial axis of rotation intersecting the first axis,and extending outwardly from the first axis, to thereby orient theleading edge of the discrete part at an angle “B” measured with respectto the second direction of travel of the receiver in the transfer zone,different in magnitude from angle “A”.

In preferred embodiments, the second driver comprises the first driverin combination with control apparatus for causing rotation of thetransport head about the second radial axis. In the alternative, thesecond driver comprises control apparatus, cooperating with motive forceprovided by the first driver, for causing the second driver to rotatethe transport head about the second radial axis while the first driverdrives the transfer assembly about the first axis.

The apparatus preferably includes suction apparatus for holding thediscrete part to the transport head between the taking zone and thetransfer zone, while the first driver drives the transfer assembly aboutthe first axis.

Preferably, the transport head has a receiving area for taking thediscrete parts, the receiving area having a roughened surface comprisinga first base surface component, and a second component comprising afirst array of protrusions extending outwardly at least about 0.006millimeter, preferably up to about 3 millimeters, more preferablybetween about 0.01 millimeter and about 0.03 millimeter, from the basesurface component for receiving the discrete parts thereunto, such thatthe protrusions on the receiving area can interact with a texturedsurface on the discrete part to thereby secure the discrete part to thetransport head.

In a fourth family of embodiments, the invention contemplates a methodof transferring discrete parts from a giver at a taking zone to areceiver at a transfer zone, the method comprising the steps ofproviding a transfer assembly, including at least one transport headmounted on the transfer assembly, the transport head having an outerwall for taking the discrete parts, and for releasing the discreteparts, the outer wall having at least one area having a roughenedsurface, the area comprising (i) a base surface component, and (ii) asecond component comprising a first array of protrusions extendingoutwardly at least about 0.006 millimeter from the base surfacecomponent for receiving the discrete parts thereunto, a second array ofsuction ports preferably being disposed in the area having a roughenedsurface, and extending through the outer wall to an interior passageinside the transport head; taking, onto the roughened surface area, adiscrete part having a textured surface wherein texture in the texturedsurface of the discrete part can interact with the roughened surfacearea of the transport head; where the suction ports are provided,optionally applying suction through the suction ports to the discretepart; and releasing the discrete part from the transport head and, wheresuction ports are optionally provided, from the suction ports.

The method further contemplates taking the discrete part as contained ina continuous web, and cutting the web to separate out the discrete partafter the taking and before releasing the discrete part from thetransport head.

The method also contemplates the transfer assembly being adapted torotate about a first axis, to take the discrete part while the discretepart is travelling at a first speed, and to release the discrete part toa receiver travelling at a second speed, and includes rotating thetransfer assembly about the first axis at a variable angular velocitysuch that the at least one transport head travels at a first surfacespeed which substantially equals the first speed of the discrete part asthe discrete part is taken onto the at least one transport head in thetaking zone, and travels at a second surface speed which substantiallyequals the second speed of the receiver as the discrete part is releasedto the receiver in the transfer zone, and further includes holding thediscrete part to the transport head, optionally with suction, whilerotating the rotatable transfer assembly from the taking zone to thetransfer zone.

The method also preferably includes taking the discrete parts while thediscrete parts are travelling in a first direction and transferring thediscrete parts to the receiver while the receiver is travelling in asecond direction, the transport head having an arcuate top wall forreceiving the discrete parts thereunto, and including orienting thetransport head such that the curvature of the arcuate top wall isdisposed transverse to the first direction of travel at the taking zone,and after taking the discrete part onto the transport head, rotating thetransfer assembly about a first axis oriented in a third directiontransverse to, and disposed in a plane parallel with, the firstdirection, and rotating the transport head about a second radial axisintersecting the first axis, thereby aligning the arcuate top wall withthe receiver at the transfer zone, such that after the rotation aboutthe second radial axis, the arcuate top wall can interact with asubstantially planar receiver disposed tangential to the orbital path,along a line transverse to the second direction in the transfer zone,and interacts with the discrete parts in the taking zone along a lineapproximating the first direction.

Finally, the fourth family of embodiments contemplates including takingthe discrete part while the discrete part is elongated and under tensionexerted by elastics integral with the discrete part, and holding thediscrete part to the transport head with sufficient e.g. suction forcethat, when the elastics integral with the discrete part are elongated bye.g. 150%, in cooperation with a friction relationship between thetransport head and the discrete part, the discrete part exhibits lessthan 50%, preferably less than 20%, more preferably less than 10%,snap-back of the elongation while the discrete part is held on thetransport head.

A fifth family of embodiments comprehends apparatus for transferringdiscrete parts from a giver at a taking zone to a receiver at a transferzone. The apparatus of this family comprises a transfer assembly; atleast one transport head mounted on the transfer assembly, the transporthead having an outer wall for taking the discrete parts, and forreleasing the discrete parts, the outer wall having at least one areahaving a roughened surface, the at least one area comprising (i) a basesurface component and (ii) a second component comprising a first arrayof protrusions extending outwardly at least about 0.006 millimeter fromthe base surface component, for receiving the discrete parts thereunto;and motive means for rotating the transfer assembly about an axis ofrotation and thereby moving the at least one transport head from thetaking zone to the transfer zone. The apparatus optionally includes asecond array of suction ports, extending through the outer wall to aninterior passage inside the transport head, and suction apparatus forapplying suction to the at least one area through the second array ofsuction ports while the transport head is moving from the taking zone tothe transfer zone.

In preferred members of this fifth family of embodiments, the motivemeans is adapted to rotate the transfer assembly about the first axis,to take the discrete part while the discrete part is travelling at afirst speed, and to release the discrete part to a receiver travellingat a second speed, including rotating the transfer assembly about thefirst axis at a variable angular velocity such that the at least onetransport head travels at a first surface speed substantially equal tothe first speed of the discrete part at the taking zone, and travels ata second surface speed substantially equal to the second speed of thereceiver at the transfer zone.

Preferably, the above recited axis of rotation comprises a first axis ofrotation, the transport head being mounted for rotation about a secondradial axis of rotation intersecting, and extending outwardly from, thefirst axis of rotation.

In a sixth family of embodiments, the invention contemplates apparatusfor intermittently applying and releasing suction to a rotating suctionhead. The apparatus comprises a tubular conduit comprising a centralsuction supply line, the tubular conduit comprising an outercircumferential wall, and having a length; a slip ring mounted forrotation about the tubular conduit, while maintaining suction sealbetween the slip ring and the tubular conduit; an enclosure comprising asuction chamber sealed to the slip ring, for rotation about the tubularconduit along with the slip ring and for applying suction to parts to beheld to an outer surface of the enclosure; a first array of suctionports in the outer circumferential wall of the tubular conduit extendingpartway, but less than all the way, about the outer circumference of thetubular conduit; and a second array of suction ports in the slip ring,longitudinally aligned along the length of the tubular conduit with thefirst array of suction ports such that, upon rotation of the slip ringabout the tubular conduit, the first and second arrays of suction portsbecome aligned for transfer of suction from the tubular conduit to thesuction chamber, through the first and second arrays of suction ports.

Preferably, the first array of suction ports in the tubular conduit isarranged about the circumferential wall of the tubular conduit such thatthe suction ports in the first array are aligned with ones of saidsuction ports in the second array, and thereby supply suction to thesuction chamber, over an angle of rotation of the slip ring of at leastabout 30 degrees, and no more than about 330 degrees.

In preferred embodiments, the slip ring comprises a first slip ring, theapparatus including a second slip ring displaced longitudinally alongthe length of the tubular conduit from the first slip ring, preferablybeside the first slip ring, mounted for rotation about the tubularconduit while maintaining suction seal between the second slip ring andthe tubular conduit, the tubular conduit having a third array of suctionports, and the second slip ring having a fourth array of suction portsfor cooperating with the third array of suction ports, to thereby supplysuction to a second suction chamber mounted to the second slip ring,over an angle of rotation of the second slip ring of at least about 30degrees, and no more than about 330 degrees.

In a seventh family of embodiments, the invention comprehends a methodof transferring a discrete part from a taking zone to a transfer zoneusing a transfer assembly having a transport head mounted thereon, thetransport head including a taking section for taking the discrete partonto the transport head, the taking section having a roughened surfacefor receiving the discrete part thereon. The method comprises the stepsof taking a discrete part onto the transport head at the taking section;holding the discrete part on the transport head by interaction between atextured surface of the discrete part and a roughened surface of thetaking section; orienting the taking segment such that the discrete partis disposed in a downward orientation such that gravity urges thediscrete part to separate from the taking section, and wherein theinteraction between the textured surface of the discrete part and theroughened surface of the taking section maintains the holding of thediscrete part on the taking section; and transferring the discrete partaway from the taking section and thus off the transport head, to areceiver, by applying an outside force to the discrete part.

In preferred embodiments, the method includes applying adhesive to thediscrete part, and drawing the discrete part away from the transporthead by contacting the adhesive with a substrate onto which the discretepart is transferred.

The method can include taking the discrete part as contained in acontinuous web, and cutting the web to separate the discrete part fromthe web after taking the discrete part onto the transport head andbefore transferring the discrete part to the receiver.

The method further comprehends taking the discrete part while thediscrete part is elongated and under tension exerted by elasticsintegral with the discrete part, and holding the discrete part to thetransport head with sufficient force that, in cooperation with afriction relationship between the transport head and the discrete part,the discrete part exhibits less than 50% snap-back of the elongationwhile the discrete part is held on the transport head.

In preferred embodiments, the method includes enhancing the holding ofthe discrete part to the transport head by applying suction through thetransport head and thus urging the discrete part toward the transporthead.

Finally, the method comprehends that the orienting of the discrete partincludes rotating the transfer assembly about a substantially horizontalaxis and thereby orienting the discrete part downwardly within 30degrees of the vertical before the transferring of the discrete partaway from the transport head.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more fully understood and furtheradvantages will become apparent when reference is made to the followingdetailed description of the invention and the drawings, in which:

FIG. 1 representatively shows a pictorial view of one example ofapparatus of the invention.

FIG. 2 representatively shows a schematic side view in elevation of theapparatus of FIG. 1.

FIG. 3A representatively shows a schematic side view in elevation ofanother example of apparatus of the invention.

FIG. 3B representatively shows a pictorial view of the apparatus of FIG.3A.

FIG. 4 representatively shows another pictorial view of the apparatus ofFIG. 3A.

FIG. 5 representatively shows another schematic side view in elevationof the apparatus of FIG. 3A.

FIG. 6 representatively shows a speed profile for a typical set ofcomplementary noncircular gears for the embodiment illustrated in FIGS.3A, 3B, 4, and 5.

FIG. 7 representatively shows a schematic side view in elevation of asingle noncircular gear set having designated angles of rotation.

FIG. 8 shows a pictorial view of a further embodiment of apparatus ofthe invention.

FIG. 9 shows a pictorial view, with parts cut away, of a portion of anincoming web to be transferred by apparatus of the invention.

FIG. 10 shows an enlarged pictorial view of the embodiment of FIG. 8,with parts cut away to show the cam system and exemplary suction portsin a slip ring.

FIG. 11 is a sectional view taken at 11—11 of FIG. 8.

FIG. 12 is a pictorial view of the crank clevis which is actuated by thecam system.

FIG. 13 is a cross section of the taking section of the outer wall ofthe transport head, with a discrete part thereon, taken at 13—13 in FIG.10.

FIG. 14 is an enlarged fragmentary pictorial view of the surface of thetaking section.

FIG. 15 is a cross-section as in FIG. 13, further enlarged to show theprotrusions.

FIG. 16 is an elevation view generally taken at 16—16 of FIG. 8.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The following detailed description is made in the context of a paperconverting process. The invention can be appropriately applied to otherflexible web processes.

The present invention provides methods and apparatus for taking discreteparts travelling at a first speed and transferring the parts to asubstrate web travelling at a second speed. The methods and apparatusare particularly useful for taking parts of an elastic material, such asleg or waist elastic, and transferring the parts to a product such as,for example, a disposable diaper or other incontinence product. It isreadily apparent, however, that the methods and apparatus would besuitable for applying any part to any suitable receiver.

Referring now to FIGS. 1 and 2, there is representatively shown anaspect of the invention wherein apparatus generally indicated at 30receives discrete parts 32 travelling at a first speed in the directionindicated by the arrow 90 associated therewith and applies the parts 32to a substrate web 34 travelling at a second speed in the directionindicated by the arrow 91 associated with the substrate web. Theillustrated example of the apparatus 30 comprises a rotatable transferassembly 40 for receiving and applying the parts 32. The apparatus 30,as representatively shown in FIGS. 1 and 2, further comprises a drivingmeans 50 for transmitting rotational energy to a driven means 60. Thedriving means 50 includes at least one rotatable noncircular drive gear54 and the driven means 60 includes at least one rotatable noncirculardriven gear 62. In use, the noncircular drive gear 54 engages androtates the noncircular driven gear 62 which, in turn, rotates thetransfer assembly 40.

The illustrated example of the transfer assembly 40 comprises at leastone shell segment 48 connected to an output shaft 64. The shell segment48 of the transfer assembly 40 may be connected to the output shaft 64by any technique known to those skilled in the art such as, for example,bolts, screws, key and matching keyways, welding and the like orcombinations thereof. For example, the shell segment 48 may be connectedto the output shaft 64 by a key inserted into mating keyways in theshell segment 48 and output shaft 64. Similarly, the other components ofthe apparatus 30 of the present invention can be connected togetheremploying the above described assembly techniques.

The shell segment 48, as representatively illustrated in FIGS. 1 and 2,can include a transport head 46 and a wall 47 connected to and extendingperpendicularly from the transport head. The web member is alsoconnected to the output shaft 64. The dimensions of the shell segment 48will vary depending upon the desired output of the transfer assembly 40and the size and shape of the discrete parts 32 being transferred. Forexample, the transport head 46 of the shell segment 48 may have an outerarcuate surface 74 spanning from about 20 degrees to about 340 degrees,a length of the outer arcuate surface of from about 1 inch to about 12inches (about 25 mm to about 305 mm), and a width of from about 0.5 inchto about 20 inches (about 13 mm to about 512 mm). As the output shaft 64rotates, the transfer assembly 40 travels in the direction indicated bythe arrow 92 associated therewith. The outer arcuate surface 74 of thetransport head, which is the circumferential, outer peripheral surfaceof the transfer assembly 40, travels along and defines an orbital path75 that passes through a taking zone 42 and a transfer zone 44. Thetaking zone 42 and the transfer zone 44 are defined by the respectivesegments of the orbital path travelled by the outer arcuate surface 74of the transfer assembly 40.

The illustrated example of the driving means 50 includes a rotatablenoncircular drive gear 54 connected to an input shaft 52. Theillustrated example of the driven means 60 includes a rotatablenoncircular driven gear 62 connected to an output shaft 64. The outputshaft 64 is parallel to, but offset from the input shaft 52, such thatthe noncircular drive gear 54 is configured to engage and rotate thenoncircular driven gear 62. The driving means 50 may include a motoroperatively connected through suitable gearing to the input shaft 52.Thus, in use, the motor rotates the input shaft 52 which rotates thenoncircular drive gear 54 which, in turn, rotates the driven gear 62,output shaft 64 and transfer assembly 40.

Alternatively, the illustrated driven means 60 may include a noncirculardriven gear 62 which is connected to a jackshaft instead of beingconnected to the output shaft 64. The term “jackshaft” connotes arotatable shaft supported in two locations that is capable of receivingthe rotational energy from the driving means 50 and transferring theenergy to the output shaft 64. The jackshaft is parallel to but offsetfrom the input shaft 52 such that the noncircular drive gear 54 isconfigured to engage and rotate the noncircular driven gear 62. Thedriven means 60 may further include a transmitting means, such as a pairof complementary gears connected to the jackshaft and output shaft 64respectively, for conducting the rotational energy from the jackshaft tothe output shaft 64 to rotate the output shaft 64 and the transferassembly 40. Alternatively, the transmitting means may include anymechanism known to those skilled in the art by which rotational energycan be conducted from one shaft to another such as, for example,circular gears, v-belts, timing belts, continuous chains and the like orcombinations thereof. Further, the transmitting means may include asecond pair of complementary noncircular gears to provide additionalspeed variations.

It will be further appreciated that the method and apparatus 30 of theinvention can utilize one or, in the alternative, two, three or morecombinations of transfer assembly 40 and driven means 60 in series toachieve the desired application of the discrete parts to the substrateweb. The different combinations may allow the use of a continuouslymoving web to supply the discrete parts. In addition, greater speedratio differentials may be achieved by using combinations of transferassembly and driven means in series. For example, referring now to FIGS.3A, 3B, 4 and 5, there is representatively shown another aspect of theinvention wherein an apparatus generally indicated at 30 receivesdiscrete parts 32 of a web of an elastic material 36 travelling at afirst speed in the direction indicated by the arrow 93 associated withthe web 36, and transfers the parts 32 to a substrate web 34 travellingat a second speed in the direction indicated by the arrow 94 associatedwith web 34. The illustrated example of the apparatus 30 comprises threeshell segments 48, represented by 40A, 40B and 40C (FIGS. 4 and 5), forreceiving and applying the parts 32. The apparatus 30 further comprisesa gearbox 56, as representatively shown in FIGS. 3A and 3B, having adriving means 50 which includes a rotatable noncircular drive gear 54for transmitting rotational energy to the three driven means 60,represented by 60A, 60B and 60C. The driven means 60, which includes arotatable noncircular driven gear 62, represented by 62A, 62B and 62C,is configured to rotate each of the shell segments 48.

As illustrated in FIGS. 4 and 5, each of the shell segments 48 isconnected to a concentric shaft 68, represented by 68A, 68B and 68C. Aseach concentric shaft 68 rotates, the transfer assembly 40 travels inthe direction indicated by an arrow 95 associated with the transferassembly. In use, the circumferential, arcuate outer surfaces 74 as seenin FIG. 1, of the respective shell segments 48A, 48B, and 48C travelalong and define the orbital path 75 that passes through taking zone 42and transfer zone 44. The taking zone 42 and the transfer zone 44 aredefined by the respective segments of the orbital path travelled by thearcuate outer surfaces of the transfer assembly 40.

The size and shape of each shell segment 48 may vary as the number ofshell segments per transfer assembly 40 changes. For example, if theapparatus includes three shell segments as representatively illustratedin FIGS. 4 and 5, each shell segment 48 may have an outer arcuatesurface which spans from about 30 to about 120 degrees of the orbitalpath 75 of the transfer assembly 40.

As illustrated in FIGS. 3A, 3B, 4 and 5, the example of the drivingmeans 50 includes the rotatable noncircular drive gear 54 connected toan input shaft 52. The illustrated example of each of the driven means60 includes the corresponding rotatable noncircular driven gear 62connected to a corresponding jackshaft 66, represented by 66A, 66B and66C. Each jackshaft 66 is parallel to but offset from the input shaft 52such that the noncircular drive gears 54 are configured to engage androtate the respective noncircular driven gears 62 thereby rotating therespective jackshafts 66. Thus, as illustrated, the single noncirculardrive gear 54 is configured to engage and rotate the three noncirculardriven gears represented by 62A, 62B and 62C which are respectivelyconnected to the three jackshafts represented by 66A, 66B and 66C. Eachdriven means 60 may further include a transmitting means 70, asrepresentatively illustrated in FIG. 3B, such as a pair of complementarygears connected to each jackshaft 66 and each concentric shaft 68respectively, for conducting the rotational energy from each jackshaft66A, 66B and 66C to the respective concentric shaft 68A, 68B and 68Cthereby rotating the respective concentric shaft 68 and transferassembly 40. Alternatively, the transmitting means 70 may include anymechanism known to those skilled in the art by which rotational energycan be conducted from one shaft to another such as, for example,circular gears, v-belts, timing belts, continuous chains and the like orcombinations thereof.

Further, each transmitting means 70 may include a second pair ofcomplementary noncircular gears to provide additional speed variations.Each transmitting means 70 may be connected to the respective jackshaft66 and concentric shaft 68 by any technique known to those skilled inthe art, such as those described above. For example, each transmittingmeans may include a pair of complementary gears connected to therespective jackshaft and concentric shaft by a key inserted into matingkeyways in the jackshaft and concentric shaft.

In operation, the driving means 50 may include a motor operativelyconnected through suitable gearing to the input shaft 52. Thus, themotor rotates the input shaft 52 which rotates the noncircular drivegear 54 which, in turn, rotates the respective driven gears 62A, 62B and62C and jackshafts 66A, 66B and 66C, which, in turn, rotate therespective concentric shafts 68A, 68B and 68C and shell segments 48A,48B, and 48C.

The apparatus 30, as representatively illustrated in FIG. 5, may furthercomprise a pinch knife cutter 84 to sever the continuously moving web ofelastic material 36 into discrete parts 32 that are fed onto each shellsegment 48. The pinch knife cutter 84 may be any mechanism known tothose skilled in the art that can sever a web of material into discretesegments such as, for example, a rotary cutter. It will be apparent thatthe continuously moving web of elastic material 36, in certain aspectsof the invention, may be omitted and the discrete parts 32 may be placeddirectly upon the transfer assembly 40. In addition, it will be apparentthat the parts 32 may be adhered to the substrate web 34 by means of anadhesive applied in a selected pattern to the surface of the parts 32,or by any other suitable means for adhering the parts to the substrateweb 34.

The use of a noncircular drive gear 54 and a noncircular driven gear 62in the apparatus 30, as representatively illustrated in the variousaspects of the invention described above, provides an inexpensive andadaptable method for receiving discrete parts 32 travelling at a speedand transferring the parts to a substrate web 34 travelling at adifferent speed. To provide the variable angular velocity, the radius ofthe noncircular drive gear, or input gear, varies. Moreover, since thecenter to center distance between the noncircular gears remainsconstant, the radius of the noncircular driven gear, or output gear,changes to correspond to the variations in the radius of the input gearsuch that the gears remain engaged or meshed during rotation. Therespective design of the noncircular gears can be controlledanalytically to obtain the desired output function. For example, thespeed profile of a typical set of complementary noncircular gears isrepresentatively illustrated in FIG. 6. Thus, the combination of thecomplementary noncircular gears 54 and 62, as used to drive the transferassembly 40 of the present invention, can provide variable angularvelocity having periods where the velocity remains constant for a fixedduration. The fixed speed dwell can be advantageous when taking thediscrete parts 32 onto the transport head 46 and when transferring themto the substrate web 34, particularly when the transfer occurs over asubstantial arc length of contact.

Noncircular gears, such as those used in the present invention, can bepurchased from Cunningham Industries, Inc. located in Stamford, Conn.Alternatively, one of ordinary skill in the art can manufacture the setof complementary noncircular gears if provided with the analyticalrepresentation of the desired output function as representativelyillustrated in FIG. 6. For example, the design of a set of noncirculargears, as representatively shown in FIG. 7, can be developed as follows.First, the output function including the required process speeds anddwells must be laid out as in FIG. 6 to determine the proper radius ofthe orbital path that the transfer assembly follows and the proper gearratios and gear angles for the noncircular gears. Secondly, thecoefficients which establish the transition or acceleration/decelerationportions of the noncircular gears, as representatively illustrated inFIG. 7, must be computed. Once the angles, ratios and coefficients areknown, the gear center to center distance is chosen from which followsthe required radii for the noncircular gears.

The radius of the orbital path is determined by calculating the totalarea under the output function curve as illustrated in FIG. 6. Theequations for doing this are:

Area=L ₁+0.5(b ₁ +b ₂)(L ₂ −L ₁)  (1)

R=Area/2 π  (2)

where:

R=radius of the orbital path (mm)

Area=area under the output function curve (mm)

L₁=low speed of the transfer assembly (mm/repeat)

L₂=high speed of the transfer assembly (mm/repeat)

b₁=total time during the trapezoidal portion of the curve (repeats)

b₂=total time to dwell at high speed (repeats)

b₃=total time to dwell at low speed (repeats)

Once the radius of the orbital path is determined, the ratios for thenoncircular gears, as illustrated in FIG. 7, are determined as follows:

θinslow=2 πb ₃  (3)

θinfast=2 πb ₂  (4)

θinaccel=2 π(b ₁ −b ₂)  (5)

θoutslow=(L ₁ b ₃)/R  (6)

θoutfast=(L ₂ b ₂)/R  (7)

θoutaccel=[2(b ₁ −b ₂)(L ₁/2+(L ₂ −L ₁)/4))]/R  (8)

Slow speed ratio=Y ₁=θoutslow/θinslow=L ₁/(2 π(R))  (9)

High speed ratio=Y ₂=θoutfast/θinfast=L ₂/(2 π(R))  (10)

Once the proper ratios and angles have been chosen, the coefficientswhich define the shape of the noncircular gears can be computed. Gearsdesigned with a sinusoidal function for the transition have been foundto give good results in practice. The equation which defines the shapeof the transitional part of the gears is given by:

η_(accel) =A−B cos(Cθ)  (11)

where η_(accel)=ratio as a function of angular position duringtransition and

A=(Y ₁ +Y ₂)/2  (12)

B=(Y ₂ −Y ₁)/2  (13)

 C=2 π/θinaccel  (14)

The actual pitch line radius of the noncircular gears can be determinedonce a choice has been made for the center to center distance betweenthe noncircular gears. The gear radius is then given by:

R _(driven gear) =D _(center)/(1+η_(accel))  (15)

R _(drive gear) =D _(center) −R _(driven gear)  (16)

where:

R_(driven gear)=The radius of the noncircular driven gear

R_(drive gear)=The radius of the noncircular drive gear

D_(center)=The desired gear center to center distance

By computing the ratios at any desired interval along the transitionusing equation (11) above, a smooth curve of the pitch line can bederived using equations (15) and (16). This smooth curve of the pitchline is used to construct a gear blank which is used to manufacture thenoncircular gears.

Thus, the design of the profile of the complementary noncircular gearscan be analytically determined to obtain the desired output functionwhich can include variable angular velocities with fixed speed dwells.One must note that when two sets of complementary noncircular gears areused the output angles of the first set become the input angles of thesecond set. In addition, all of the angles on the gears must add up to 2π radians or 360 degrees.

As compared to conventional methods, such as the slip gap methoddescribed above, for changing the speed of a discrete part such that itcan be applied to a continuously moving web, the use of noncirculargears provides the ability to obtain greater changes in speed and tomaintain constant speeds for a fixed duration. The fixed speed dwellachieved by using noncircular gears can be accurately and inexpensivelydesigned to precisely control the length and placement of the discreteparts 32. For example, in the various aspects of the invention, theprofile of the noncircular gears 54 and 62 is analytically designed suchthat the rotatable transfer assembly 40 receives discrete the parts 32in the taking zone 42 while maintaining a constant surface speedsubstantially equal to the incoming speed of the parts 32. Moreover, theprofile of the noncircular gears 54 and 62 is designed such that thesurface speed of the rotatable transfer assembly 40 changes to a secondconstant surface speed as the rotatable transfer assembly 40 moves fromthe taking zone 42 to the transfer zone 44. The term “surface speed,” asused herein, refers to the speed of the circumferential, outerperipheral surface of the transfer assembly 40 as defined by arcuateouter surfaces 74 of the respective transport heads 46. The profile ofthe noncircular gears can be designed such that the speed of thediscrete parts 32 being transferred is substantially equal to the speedof the substrate web 34 as the discrete parts are applied to thesubstrate web in the transfer zone 44. The surface speed of the transferassembly 40 is maintained substantially constant in the taking zone 42and the transfer zone 44 for from at least about 0 to about 300 degreesof rotation, desirably from about 10 to about 300 degrees of rotation,and more desirably from about 120 to about 240 degrees of rotation ofthe transfer assembly 40. In addition, the surface speed increase ordecrease of the transfer assembly 40 as it moves from the taking zone 42to the transfer zone 44 defines a speed ratio of from at least about0.9:1 to about 20:1, desirably from about 0.9:1 to about 10:1, and moredesirably from about 0.9:1 to about 4:1. The term “speed ratio”, as usedherein, defines the ratio of the surface speed of the transfer assembly40 as the parts 32 are applied to the substrate web 34 to the surfacespeed of the transfer assembly 40 as the parts 32 are taken.

The transfer assembly 40, as representatively illustrated in the variousconfigurations of the invention, includes the transport head 46, asrepresentatively illustrated in e.g. FIGS. 1 and 5, to grip the discreteparts 32 in the taking zone 42 and to transport the parts to thetransfer zone 44. In a particular aspect of the invention, the transporthead 46 may include a suction means for providing a region of relativelylow pressure. The suction means may include ports through which asuction may be selectively imposed. Thus, the suction may be activatedin the taking zone 42 and deactivated in the transfer zone 44 as thepart 32 is applied to the substrate web 34. In this manner, positivecontrol is maintained over the parts 32 at all times during the transferprocess since, in these embodiments, there is no time at which the partsare free of the holding action provided by the transport head 46.Alternatively, the transport head may include any conventional techniqueknown to those skilled in the art for holding and releasing parts suchas, for example, mechanical clamps, electrical clamps, magnetic clampsand the like or combinations thereof.

The various aspects of the apparatus 30 may further comprise an infeedconveyor 80 and an outbound article conveyor 82 as representativelyillustrated in FIG. 1. The infeed conveyor 80 may supply the discreteparts 32 to the transfer assembly 40. The outbound article conveyor 82may carry the substrate web 34.

The method and apparatus of the present invention may be used in themanufacture of articles such as diapers, training pants, and adultincontinence products, among other uses. The method and apparatus may beused to apply discrete parts or components, such as, for example, waistelastic, leg elastic, tapes, snaps and hook and loop materials to thediaper or incontinence product. Articles such as diapers andincontinence products are described, for example, in U.S. Pat. No.4,704,116 issued Nov. 3, 1987, to Enloe; U.S. Pat. No. 4,798,603 issuedJan. 17, 1989, to Meyer et al.; U.S. Pat. No. 4,710,187 issued Dec. 1,1987, to Boland et al.; U.S. Pat. No. 4,770,656 issued Sep. 13, 1988, toProxmire et al.; and U.S. Pat. No. 4,762,521 issued Aug. 9, 1988 toRoessler et al.; the disclosures of which are incorporated herein byreference.

In a particular aspect, the apparatus 30 of the invention, such as theconfigurations representatively shown in FIGS. 3A, 3B, 4 and 5, may beused to apply parts of leg elastic to a disposable diaper. For example,a continuously moving web of elastic material 36 is fed into the pinchknife cutter 84. The pinch knife cutter 84 severs the web of elasticmaterial 36 into discrete parts 32 which are fed onto the transferassembly 40 in the taking zone 42. As transfer assembly 40 rotates, theparts of leg elastic 32 are held onto the transfer assembly 40 bytransport head 46 which includes suction. The suction is activated inthe taking zone 42 and deactivated in the transfer zone 44 as the parts32 are transferred to the substrate web 34. The driving means 50 anddriven means 60 which, in combination, rotate the transfer assembly 40include a pair of complementary noncircular gears 54 and 62. The profileof the noncircular gears 54 and 62 is designed as described above suchthat, as the noncircular gears 54 and 62 and transfer assembly 40rotate, the transfer assembly 40 maintains a substantially constantsurface speed as the parts of leg elastic 32 are taken and transferred.For example, the transfer assembly 40 receives the parts of leg elastic32 in the taking zone 42 while maintaining a constant surface speedsubstantially equal to the speed of the web of elastic material 36. Thesurface speed of the transfer assembly 40 then changes to a secondconstant surface speed such that the speed of the parts of leg elastic32 being transferred is substantially equal to the speed of the diaperweb 34 as the parts of leg elastic 32 are applied to the diaper web 34in the transfer zone 44. The surface speed of the transfer assembly 40is then changed back to substantially equal the speed of the web ofelastic material 36.

The parts of leg elastic 32 being applied to the diaper web 34 may bemade of any suitable material having elastic or stretchable properties.Examples of such materials include films or layers of natural rubber,synthetic rubber, or thermoplastic elastomeric polymers, and can bepanels, or single, or multiple threads or filaments or ribbons thereof.These materials may also be heat-shrinkable or heat-elasticizable.Furthermore, these stretchable materials may be formed with gatherablelayers, such as spunbonded polymer materials, as a stretch-bondedlaminate. For example, a suitable stretch-bonded laminate comprises twogatherable layers of 0.4 ounce per square yard of spunbond polypropylenehaving therebetween a layer of meltblown elastic material such as aKraton elastic in either layer form or separate threads of materialhaving a basis weight of about 0.5 ounce per square yard. The layer ofthe elastomeric is stretched, the two layers of polypropylene thenjoined to the elastomeric layer, and upon relaxing the layers, thepolypropylene layers gather. The materials may be breathable ornonbreathable.

Referring now to FIG. 8, there is representatively shown another aspectof the present invention wherein an apparatus generally shown at 130receives discrete parts 132 as part of webs 136 travelling at a firstspeed in the direction indicated by the arrow 100 associated therewithand transfers the parts 132 to a substrate web 134 travelling at asecond speed in the direction indicated by the arrow 101 associatedtherewith.

Referring to FIGS. 8-10, incoming webs of material 136 comprise firstand second layers 230A and 230B of spunbonded polypropylene (0.7 ouncesper square yard), and a plurality of threads 232 of elastic adhesivelysecured between the layers 230A and 230B. The elastic can be any of avariety of elastics suitable for providing the elastic property in theweb 136. In a web 0.625 inch wide, suitable elasticity is provided byfour threads of 940 decitex lycra generally uniformly spaced across thewidth of the web.

In the example illustrated in FIGS. 8 and 11 the rotatable transferassembly 140 includes three shell segments 148A, 148B, and 148C,supported by concentric shaft 168 and tubular suction conduit 158.

Referring now to FIGS. 8-11 in combination, the drive system in gearbox156, operating through concentric shaft 168, causes the shell segments148A, 148B, and 148C to rotate about the concentric shaft 168 andtubular suction conduit 158. As the shell segments 148 rotate about afirst generally horizontal axis 178 of the transfer assembly 140, a cammechanism generally designated 172 rotates the transport head 146 abouta radial axis 176 which intersects the generally horizontal axis 178 ofthe transfer assembly.

Accordingly, as shown in FIGS. 10, 11 and 16 starting from the takingzone 142, the arcuate top wall 174 of the transport head is disposedtransverse to the direction of travel of the incoming web 136 of elasticmaterial as the respective transport head picks up the incoming elasticmaterial. The cam mechanism 172 then rotates the transport head 90degrees about radial axis 176 by the time it reaches the transfer zone144, and rotates it back the same 90 degrees by the time it returns tothe taking zone.

Cam mechanism 172 includes an external cam 102 extending outwardly from,and circumferentially about, drum 104 which is fixedly mounted to thegearbox 156. A pair of cam followers 106 connected to each shell segmentfollows the cam 102 about the perimeter of the drum 104. Push rod 108extends from cam followers 106 toward the respective transport head 146,and connects to actuating arm 110 through pin 112. Actuating arm 110connects to the respective transport head 146 through pin 113 and crankclevis 114, as is discussed hereinafter. Accordingly, the reciprocatingmotion of push rod 108, as suggested by the double headed arrow 96,causes corresponding rotation of the respective transport head 146 asthe respective shell segment 148 traverses the orbital path 175.

Referring especially to FIG. 11, the stationary tubular suction conduit158 is mounted to the rotating concentric shaft 168 through shaftsegment 168A and bearings 116. Shell segment 148A is mounted to tubularconduit 158 through bearing 118A. Similarly shell segments 148B and 148Care mounted to tubular conduit 158 through bearings 118B and 118Crespectively.

Shell segment 148A is mounted to concentric shaft member 168A by bolt120A. Similarly shell segments 148B and 148C are mounted to concentricshaft members 168B and 168C by bolts 120B, and 120C. Bolt 120C is notshown.

Slip ring 119A is bolted to shell segment 148A by bolts 121, and extendsabout, and is mounted for rotation about tubular suction conduit 158 ata fixed longitudinal location along the length of the conduit. A firstarray of suction ports 122A is disposed circumferentially about theouter wall of the conduit 158 along a portion of the path of rotation ofslip ring 118A. FIGS. 10 and 11. A second array of suction ports 123A isdisposed about a portion of the circumference of slip ring 119A adjacentshell segment 148A, and in alignment with the first array of suctionports in the conduit 158. Conventional suction seals (not shown) areused between the slip ring and the outer circumferential wall of theconduit 158. Accordingly, as the slip ring 119A rotates about conduit158 with shell segment 148A, the second array of suction ports on theslip ring comes into alignment with the first array of suction ports onthe conduit. Upon such alignment, suction is effected between conduit158 and the interior chamber 124A of the shell segment 148A, as shown inFIG. 11. Correspondingly, the suction in the interior chamber 124A istransferred to transport head 146A through a third array of suctionports 126A in the top cover 128A of shell segment 148A. Crank clevis 114(FIG. 12) is mounted to shell segment 148A by upper and lower bearings198, 199. A pair of arms 200 extend outwardly from the main body 201 ofthe crank clevis, for receiving the actuating arm 110A. A pair of upperand lower generally circular bearing posts 202, 204 extend upwardly anddownwardly, respectively, from the upper and lower surfaces of arms 200and engage the upper and lower bearings 198, 199. Male slot key 206extends upwardly from the upper bearing post 202.

Transport head 146A has a main body 208. Female slot 209 correspondswith, and receives, male slot key 206 on the crank clevis 114. Transporthead 146A is secured to crank clevis 114, through male slot key 206 andfemale slot 209, using a pair of bolts 210. Accordingly, when the femaleslot 209 is engaged with male slot key 206, rotational motion of thecrank clevis 114 causes corresponding rotational motion in the transporthead 146A.

The main body 208 of the transport head extends to an outer arcuate topwall 212, shown in FIG. 11. A suction seal 214 extends in a circularpath, on transport head 146A, about the third array of suction ports126A, providing a suction seal between the interior chamber 216 of thetransport head and the top cover 128 of shell segment 148A. The thirdarray of suction ports 126A is disposed radially about crank clevis 114,in a generally circular arrangement, such that suction in the interiorchamber 124A of the shell segment is readily transmitted into theinterior chamber 216 of the transport head.

The arcuate top wall 212 of the transport head 146 includes a takingsection 218. Referring to FIGS. 10 and 13-15, each taking section 218has a length “L” and a width “W”, with the length being disposed in adirection transverse to the arc of the arcuate top wall 212, wherebyeach taking section 218 lies within generally a constant portion of thecorresponding arcuate outer surface 174 along its entire length.

As seen in FIG. 13, each taking section 218 includes a substrate portion220 extending above the main level 221 of the arcuate outer surface 174of top wall 212 of transport head 146, and a roughened coating 222.

While not critical, and while no dimensions are considered controlling,the substrate portion 220 is preferably raised e.g. about 0.005 inch toabout 0.125 inch above the main level 221 of the arcuate outer surfaceof the top wall 212, to facilitate performance of the taking sections.The roughened coating 222 can be characterized as any coating thatprovides a base surface component 223 overlying the substrate portion220, and an array of protrusions 225 extending from the base surfacecomponent. The protrusions 225 extend at least 0.006 millimeter from thebase surface component, with a range of about 0.01 millimeter to about0.03 millimeter being preferred. Any upper limit to the length of theprotrusions depends on the characteristics of the discrete parts to betransferred by the transport head. However, typically the protrusionswill not extend more than about 3 millimeters from the base surfacecomponent.

In preferred embodiments, the roughened coating 222 has releasecharacteristics at least as good as those of Teflon®polytetrafluoroethylene. However, a variety of release characteristicsare acceptable, depending on the remainder of the process. A preferredcoating is a plasma coating supplied as coating 902EA from PlasmaCoatings, Inc., Waterbury, Conn.

The spacing between the protrusions 225 in the array of protrusionspreferably is selected in view of the texture of the surface of therespective discrete part 132 which faces the transport head. Theprotrusions 225 should be spaced far enough apart to engage any surfacetexture of the discrete part, and close enough together to havesufficient engagement with elements of the parts 132 to provide asignificant interaction between the elements of the parts and theprotrusions on the coating. Thus, in applicants' contemplatedapplication wherein the discrete parts are made with spunbonded and likematerial, the protrusions should be spaced far enough apart that thefibers 227 can descend into the valleys 229 between the protrusions 225,and thereby engage the sidewalls of the valleys, to thereby fix thefibers, and correspondingly, the parts, in position on the takingsections 218.

“Textured surface” and “texture” of the surface of the parts 132 refersto any irregularities in the respective surface of the part that giveseffective third dimension to the surface. Thus, for example, the fibersin nonwoven or woven fabrics comprise irregularities. Similarly, anemboss pattern in an otherwise smooth surface layer of film or nonwovenfabric would comprise a texture. Irregularities may be uniformly spacedas in a repeat emboss pattern or woven fabric, or spaced randomly aswith nonwoven fibers.

The widths across the valleys in the projection matrix are necessarilyless than the cross-sections of the fibers in the outer layers 230 ofthe webs 136 seen in FIG. 9. As the webs 136 are drawn onto the takingsections 218, the fibers 227 in the corresponding spunbonded outer layer230 interact with the roughened surface provided by the plasma coating222, wherein the individual fibers become drawn below the tops of theprotrusions 225 and into the intervening valleys 229, thereby creatingstresses in the matrix of the spunbonded material which interact withthe protrusions on the corresponding taking section to hold the discreteparts securely in a fixed position on the taking section, andcorrespondingly, maintaining the existing elongation of the respectivediscrete parts.

Referring to FIGS. 11 and 13, an array of suction ports 224 extendthrough the substrate 220 and coating 222 of the taking section, thusapplying the suction to the discrete parts as they are disposed on theouter arcuate surface (e.g. the taking sections 218) of the top wall 212of the corresponding transport head 148.

As shown in the drawings, and especially referring to FIG. 11, shellsegments 148B and 148C preferably correspond in general with thestructure disclosed for shell segment 148A, with corresponding provisionfor bearings 118B and 118C, slip rings 120B and 120C, and concentricshafts 168B and 168C. Similarly the cam mechanism is preferably the samefor all shell segments.

It is contemplated that the operation and functions of the inventionhave become fully apparent from the foregoing description of elementsand their relationships with each other, but for completeness ofdisclosure, the usage of the embodiment illustrated in FIGS. 8-15 willbe briefly described hereinafter.

Adhesive is applied to the incoming elastic webs of material 136 byadhesive applicators 226, and is cooled by turning roll 228, which alsoturns the elastic webs into alignment with the corresponding transporthead 146C on the transfer assembly 140.

The surface driving speed of the transfer assembly is faster than thecorresponding driving speed of the elastic thread unwind (not shown).Accordingly, in the embodiment shown, the elastic threads 232 areelongated up to about 300% from their relaxed length. Thus, the webs 136are under tension exerted by the elastic threads 232 as the webs aretaken onto the transport head 146C.

As seen in FIGS. 8-16, the arcuate outer surface 174 of the transporthead is oriented transverse to the direction of travel of the incomingwebs 136 at the respective transport head. Suction is activated on thetaking sections of the transport head 146C as transport head 146Crotates into position to take the incoming webs onto its takingsections. As the transfer assembly continues to rotate about itshorizontal axis 178, the taking sections of the transport head 146C takeand hold corresponding portions of the webs 136, thus continuing thedrawing of the webs 136 into the transfer assembly. Accordingly, theleading edge of each part 132 is oriented at an angle “A” transverse tothe direction in which the part is travelling when the part is takenonto the transport head in taking zone 142.

As the transfer assembly 140 rotates under the driving force of thedriving means 50 and the gearbox 156, the webs 136 are severed intoindividual discrete parts 132 by a heated knife or other cutter 184 asseen in FIG. 16.

The elongation of the individual discrete parts is maintained by thecombination of the protrusions 225 of the plasma coating 222 and thesuction through the suction ports 224. FIG. 14 illustrates a typicalsuction port pattern for a taking section approximately 0.5 inch wide.

Without plasma coating 222, and using 45 inches of water, suction, theabove web material 136, including layers 230A, 230B of 0.7 ounce persquare yard spunbonded polypropylene and four threads of 940 decitexlycra, after being severed by heated cutter 184, exhibits greater than10% snap-back. Using the plasma coating 222, and using only one inchwater of suction, snap-back is less than 10% retracts to length shorterthan 90% of the length, L₁, as shown in FIG. 6. Both the amount ofsuction, and the characteristics of the coating material 222 can beadjusted to affect the amount of snap-back tolerated by thespecifications of the material being processed and the product beingmade. The amount of snap-back increases as the amount of suction isdecreased. Snap-back also increases as the character of the coatingmaterial 222 changes to reduce the amount of entanglement between thefibers or other texturing of the surface of layers 230 and theprotrusions 225.

While the plasma coating 222 is preferred, other types of coatings canbe used to provide the protrusions 225. For example, conventional emerypaper or the like can be used; but the corresponding emery papersubstrate does not exhibit the beneficial long term wear characteristicsof the plasma coating. So the plasma coating is preferred.

As the transfer assembly 140 continues to rotate, the transport head146C moves around to the positions shown in FIG. 10 for transport heads146A and 146B. By the time the transport head reaches the position shownfor transport head 146B, the cam 102, acting through connecting linkagesof cam follower 106, pushrod 108, actuating arm 110, pin 112, pin 113,and crank clevis 114 rotates the transport head such that it is oriented90 degrees about the radial axis 176 to the position shown for transporthead 146B in FIGS. 8 and 10, wherein the leading edge of the part isparallel to the direction of travel on the transfer assembly, and by thetime the discrete part 132 reaches receiving web 134, parallel to thedirection of the receiving web. At about the position shown fortransport head 146B in FIG. 8, the non-circular gears in gearbox 156cause an increase in the radial velocity of the corresponding transporthead as described above with respect to FIGS. 6 and 7. By the time thetransport head reaches the receiving web 134 at the transfer zone 144,the surface speed of the discrete parts 132 generally corresponds withthe surface speed of the web 134.

Adhesive applied at adhesive applicators 226 is then activated. As thediscrete parts 132 contact the web 134, the suction is released as thecorresponding slip ring reaches the end of the corresponding array ofsuction ports 122 in the conduit, and the adhesive attraction betweenthe discrete parts 132 and the web 134 causes the discrete parts totransfer to the receiving web 134.

The noncircular gears then cause a decrease in the radial velocity ofthe corresponding transport head such that, by the time the transporthead returns to the taking zone 142 and to receive another portion ofthe incoming web 136, the surface speed of the transport head matchesthe surface speed of the incoming webs 136. As the transport head againpicks up a portion of the incoming web 136, the corresponding slip ring118 reaches the beginning of the corresponding array of suction ports122 in the conduit, thereby activating suction on the correspondingtransport head, to begin another cycle.

As used herein, “transverse” direction, when referring to rotation ofthe discrete parts means anything not aligned with the first directionof travel of the receiving web 36 or 136, and not 180° from the firstdirection.

Having thus described the invention in full detail, it will be readilyapparent that various changes and modifications may be made withoutdeparting from the spirit of the invention. All such changes andmodifications are contemplated as being within the scope of the presentinvention, as defined by the following claims.

What is claimed is:
 1. A method for taking discrete parts travelling ata first speed in a first direction, and transferring the discrete partsto a receiver travelling at a second speed in a second direction, saidmethod comprising the steps of: a) providing a rotatable transferassembly, and at least one transport head mounted on the transferassembly, for taking the discrete parts onto the at least one transporthead in a taking zone, and for transferring the discrete parts to thereceiver in a transfer zone; (b) taking the discrete part onto the atleast one transport head in the taking zone wherein a leading edge ofthe discrete part is oriented at a first angle with respect to the firstdirection of travel; (c) after taking the discrete part onto the atleast one transport head, (i) rotating the rotatable transfer assemblyabout a first axis oriented in a third direction transverse to, anddisposed in a plane parallel with, the first direction, at a variableangular velocity such that the at least one transport head travels at afirst surface speed which substantially equals the first speed of thediscrete part as the discrete part is taken onto the at least onetransport head in the taking zone, and travels at a second surface speedwhich substantially equals the second speed of the receiver as thediscrete part is transferred to the receiver in the transfer zone, and(ii) rotating the transport head about a second axis which is radial tothe first axis intersecting the first axis and extending outwardlytherefrom, to thereby orient the leading edge of the discrete part at asecond angle measured with respect to the second direction of travel ofthe receiver in the transfer zone, different from the first angle; and(d) transferring the so rotated discrete part to the receiver in thetransfer zone.
 2. A method as in claim 1 and including applying adhesiveto the discrete part, and drawing the discrete part away from thetransport head by contacting the adhesive with a substrate onto whichthe discrete part is transferred.
 3. A method as in claim 1, andincluding rotating the transport head about the second axis which isradial to the first axis while simultaneously rotating the rotatabletransfer assembly about the first axis.
 4. A method as in claim 1, andincluding taking the discrete part in subparagraph (b) as contained in acontinuous web, and cutting the web to separate out the discrete partafter the taking of step (b) and before rotating the transport headabout the second axis which is radial to the first axis in step (c). 5.A method as in claim 1, and including holding the discrete part to thetransport head with suction while rotating the rotatable transferassembly from the taking zone to the transfer zone.
 6. A method as inclaim 5, and including holding the discrete part to the transport headwith at least about 1 inch of water suction.
 7. A method as in claim 5,and including providing suction through the transport head, to enhancethe holding of the discrete part to the transport head.
 8. A method asin claim 1 and including providing, on the transport head, a takingsection having a roughened surface, and providing, on the discrete part,a textured surface, the textured surface of the discrete partinteracting with the taking section of roughened surface on thetransport head to thereby secure the discrete part to the transporthead.
 9. A method as in claim 8, and including providing suction throughthe transport head, to enhance the holding of the discrete part to thetransport head.
 10. A method as in claim 1, said transport head havingan arcuate top wall for receiving the discrete parts thereunto, themethod including orienting the transport head such that the curvature ofthe arcuate top wall is disposed transverse to the first direction oftravel at the taking zone, and rotating the transport head about thesecond axis which is radial to the first axis after taking the discretepart onto the transport head, and thereby aligning the arcuate top wallwith the receiver at the transfer zone, whereby, after the rotationabout the second radial axis, the arcuate top wall can interact with asubstantially planar receiver disposed tangential to the orbital path,along a line transverse to the second direction in the transfer zone,and interacts with the discrete parts in the taking zone along a lineapproximating the first direction.
 11. The method of claim 1 furtherincluding rotating said transport head in said taking zone at a velocitywhereby said discrete parts are elongated up to about 300%.
 12. A methodas in claim 11 further including holding the elongated discrete part tothe transport head with sufficient force that, in cooperation with afriction relationship between the transport head and the discrete part,the discrete part exhibits less than 50% snap-back of the elongationwhile the discrete part is held on the transport head.